99 STS trans fluid

Hello everyone. Well, I'm no longer an eldorado owner. I've stepped up a bit to a 99 Seville. Just bought it and found the trans fluid to be worn. It's not its usual bright red color and almost seems thin. It's got 121,k miles and trans life indicator is at 100% (imagine that). Should I get the fluid and filter changed anyway? I know its a dumb question, but I've been told that changing the fluid that high and bringing in new fluid will cause tranny problems sooner. So, I'm here asking the greats because I'm not a mechanic and transmissions are far out of my realm.

Re: 99 STS trans fluid

Spend the money at either a GM dealer or a good transmission shop and ask for a transmission fluid exchange to the new (2006) DEXRON-VI - it is 100% backwards-compatible with the obsolete DEXRON-III that came in our cars. I did my 2002 in 2007 and nary a problem.

Remember that the 4T80E is a dry sump transmission - there will be NO FLUID on the stick with the engine OFF. Check/adjust level with the engine hot (> 10 mile drive) idling in P on a level surface.

Re: 99 STS trans fluid

easy to check level with motor running. you remove fill port cover and look in. you can see fluid level in port. your car is 14yrs old. it could use dex6 but it will work fine with dex3 which is still easy to find. unless you go to dealer.

Re: 99 STS trans fluid

Should I get the fluid and filter changed anyway?

There is not filter to change. Just 2 cleanable and reusable screens. Likewise the gasket is reusable.

Personally I'd drop the pan so as to clean the magnets and any other debris that may be in there. Start the engine while the pan is down to pump out most of the rest of the old fluid (might get messy). Button it up and refill.

oil changes cost 80 each yr and a trans fluid swap might cost 40 which you may do every 3-4 yrs. kids vue uses t-4 toyo fluid which is 5 at toyo garage or 16 at gm garage. yep, 64 per gal at gm. u would think it was bottled french water. Or royal purple

Re: 99 STS trans fluid

^^^ You'll be able to change just about half of the fluid with a pan drop/side tank drain - 7 or 8 quarts.

You can exchange about 13+ (of the 15) quarts by doing the upper cooler line pumpout method.

That's my plan. I hope to get to it this weekend. Valvoline Dexron VI - $8/qt
Right now the A/C isn't cooling so I need to put the gauges on her. Can't complain though for a '99 that has never had any cooling problems 'til now.

Re: 99 STS trans fluid

Wow! I've been busy all day. I come and there's 11 posts! Thanks for answering and discussing here; I've learned a bit by reading what's been said so far. I think I'm going to price fluid tomorrow here locally. Do I need a specific solution for the screens shoukder I decide to do it myself? What are the advantages of dex 6 compared to dex 3? If I go with dex 6, should I just have the dealer do a complete fluid swap?

Re: 99 STS trans fluid

is price a big deal? amsoil is 11/qt. royal purple is 15. valvoline dex3 is 5. i think dealer dex6 is 9. a 2005 car has dex6. it needs dex6. your car was built with dex3. many say its ok to continue to use dex3 if you want or pay double and use dex6. it wont shift better. the most praise i hear is it wont shift worse. thats pretty damn faint praise.